1. Field of the Invention
The present invention relates to flame retardant flexible polyurethanes, foam compositions and more particularly to such compositions incorporating pentabromodiphenyl ether in combination with mixtures of halogenated alkyl phosphate esters containing aliphatic bromine and chlorine.
2. Description of the Prior Art
The need to reduce the flammability of polymeric systems while not adversely affecting the chemical, physical and mechanical properties or the appearance of polymeric systems is disclosed in the Encyclopedia of Polymer Science and Technology, Volume 7, pp. 1-3 and The Encyclopedia of Chemical Technology, 3rd Edition, Volume 10, p. 48.
Phosphorous-halogen systems have been widely used to flame retard polymeric systems. For example, the use of certain pentavalent phosphate esters containing bromine and chlorine as flame retardants is taught by Birum, et al., U.S. Pat. No. 3,132,169.
Other patents disclosing halogenated phosphate esters include Birum U.S. Pat. Nos. 3,192,242 and 3,344,112; Carpenter 3,324,205; Jenkner, et al. 3,781,388; Dow, et al. 3,830,886; Wilkinson 3,997,449; Stanaback 4,046,719; Albright 4,083,826 and 4,240,953; and West German OS 2,416,663. Albright, et al. U.S. Pat. No. 4,083,825 discloses the use of bis(2-chloroethyl) 2,2-dimethyl-3-bromopropyl phosphate as a flame retardant for polyurethane foams. Albright, et al. U.S. Pat. No. 4,696,963 discloses the use of flame retardant non-mutagenic mixtures of three halogenated alkyl phosphates and their use as flame retardants for various polymeric systems including flexible polyurethanes.
Pentabromodiphenyl ether is a halogenated aromatic flame retardant that has been employed in various polymeric systems. However, the prior art has not heretofore shown or suggested that combination of halogenated alkyl phosphates and pentabromodiphenyl ether would have any special advantages.
It is, thus, a primary object of this invention to provide highly effective flame retardant additive compositions of pentabromodiphenyl ether and mixtures of halogenated alkyl phosphates.
It is also an object of the present invention to provide effectively flame-retarded flexible polyurethane foams incorporating flame retardant additive composition of the character described.